Research On Slippage And Deceleration Prediction Of Hoist Based On Inital Braking Parameters

Mine hoist is an important equipment in mining activities of mine industry,which undertakes the transportation of minerals,tools and equipment and personnel.In recent years,with the increasing demand for resources and the depletion of shallow earth resources,the demand for deep earth resources mining activities has been increasing,which has promoted the development of mine hoists to large-scale,heavy-duty and high-speed operation.Because the mine hoist is driven by wire rope,which belongs to a typical flexible transmission system,it is easy to produce severe shock and vibration during emergency braking.Therefore,with the increase of lifting load,running speed and lifting height,the vibration and impact phenomenon of hoist during emergency braking will be more serious,and even lead to serious consequences of slipping and breaking of wire rope.How to reduce the impact and vibration of mine hoist during emergency braking is an important guarantee for the safe operation of large mine hoist.In view of this problem,this paper intends to study the limit deceleration and slip characteristics of mine hoist when emergency braking occurs.Taking the multirope friction mine hoist as the research object,the slip characteristics of the hoist under different working conditions are simulated and analyzed.The machine learning algorithm is applied to the prediction of the limit deceleration of the hoist and the judgment of the slip characteristics.The influence of the characteristic variables such as running direction,lifting speed,lifting load and lifting height on the target label value is analyzed,and the algorithm model established is applied to predict the limit deceleration of hoist under any working condition and to judge the slip characteristics of the hoist system.The research results will provide a basis for the design of the mine hoist emergency braking system strategy.Modeling and dynamic simulation analysis of mine hoist simulation model: Based on the parameters of JKMD3.25*4(II)floor type multi-rope friction mine hoist,a rigid-flexible coupling dynamic simulation model of multi-rope friction mine hoist is established.In the process of modeling,not only the structural parameters of each component are considered,but also the contact between the lifting wire rope and the friction reel,the elastic connection between the guide wheel and the cage in the cage system,and the contact effect between the guide wheel and the channel are considered.The model is validated and optimized by using the test data collected from the field.The dynamic characteristics of the hoist during constant deceleration braking and the influence of different lifting parameters on the dynamic characteristics of the hoist are analyzed through simulation.Analysis of slip characteristics of hoist during emergency braking: Guided by the anti-skid theory of the friction lifting system,a large number of simulation calculations are used to study the abrupt change point of the hoist from no skidding to skidding under different working conditions to obtain the limit deceleration simulation value of the hoist under various working conditions.And calculate the theoretical value of the limit deceleration under the corresponding working conditions,compare the simulated value with the theoretical calculated value.The comparison results show that the simulation value of the limit deceleration is less than the theoretical calculation value,and the error of the two gradually decreases with the increase of the load in the heavy load lowering condition,and the error of the two is basically independent of the load change in the heavy load lifting condition;the influence of the lifting height and the lifting speed on the limit deceleration of the hoist is very small,and the relationship between the load and the limit deceleration in the heavy load lowering condition is approximately linear: under the heavy load lowering conditions,the load and the limit deceleration are approximately linear and decrease with the increase of the load;under the heavy load lifting condition,the load and the limit deceleration are approximately linear and increase with the increase of the load.Research on prediction algorithms of braking deceleration and slipping characteristics of hoist based on initial braking parameters: The limit deceleration of hoist under different working conditions and the original data set of hoist slipping state are obtained by simulation,the importance of each characteristic variable in the original data sets and its correlation with the target value are analyzed by using the algorithm.The random forest regression algorithm and classification algorithm are used to establish the prediction model of hoist ultimate deceleration and the prediction model of hoist slip characteristics,the parameters of the model are optimized for the prediction of hoist ultimate deceleration and the judgment of hoist slip characteristics.The minimum mean square error of the regression model is 0.0157 by comparing the predicted results of the random forest regression algorithm with those of the multiple linear regression and ridge regression.The highest accuracy of the classification model is 91.7% by comparing the predicted results of the random forest classification algorithm with those of the support vector machine and the gradient boosting decision tree algorithm.